Epinephrine accumulation in rat brain after chronic administration of pargyline and LY 51641--comparison with other brain amines

Concentrations of biogenic amines and metabolites were measured in regions of rat brain following administration of monoamine oxidase (MAO) inhibitors for 21 days. Epinephrine concentrations were increased from 350 to 500% following chronic administration of LY 51641, a selective inhibitor of MAO type A. Norepinephrine, dopamine and serotonin showed much less relative accumulation. The marked relative accumulation of epinephrine may be related to the efficacy of inhibitors of MAO type A in the treatment of depression.